The invention relates to fuel manifolds for the fuel system of an internal combustion engine.
A fuel rail or manifold supplies fuel to a plurality of fuel injectors that inject the fuel into the corresponding inlet ports of the engine. Electromagnetic fuel injectors deliver fuel to the engine in metered pulses which are appropriately timed to the engine operation. The sequential energization of the fuel injectors induces within the fuel manifold pressure pulsations that create various problems including improper fuel distribution to the injectors, which can adversely affect tailpipe emissions and driveability, and fuel line hammering, which results in vibration and audible noise.
It is known to utilize a damper inside the fuel manifold to effectively minimize or dampen the pressure pulsations created by the fuel injectors. Using a damper increases the installation and assembly time of the fuel manifold, and thus increases the overall cost.
It is also known to utilize a fuel manifold that does not need a damper to reduce the pressure pulsations. An example of such a self-damping manifold is disclosed in U.S. Pat. No. 4,660,524 issued Apr. 28, 1987.
The fuel manifold of the present invention eliminates the need for a separate damper and provides greatly improved damping characteristics. The invention provides a simple and inexpensive one-piece extruded aluminum fuel manifold designed with optimum self-damping characteristics.
More specifically, the invention provides a fuel manifold having a rigid base portion with a fuel injector pocket defined therein, a top wall portion, a first substantially flat thin-walled portion extending between the rigid base portion and the top wall portion and a second substantially flat thin-walled portion extending between the rigid base portion and the top wall portion. The entire manifold is a one-piece aluminum extrusion and defines a fuel cavity that extends into the base portion and communicates with the fuel injector pocket.
The width of the fuel cavity in the base portion is preferably less than the width of the fuel cavity between the first and second thin-walled portions, and is preferably approximately one half of the width of the fuel cavity between the first and second thin-walled portions. Furthermore, the top wall portion and the first and second thin-walled portions define an upper portion that is preferably substantially rectangular in cross-section and has a width that is approximately one half the width of the base portion.